The "undesigned coincidence" between Mark and John on the temple statement: Mark records the false witnesses misquoting Jesus about destroying and rebuilding the temple, but never explains the original statement. John 2:19-21 records the original statement and clarifies it referred to his body. Neither account is copied from the other; they lock together in a way that supports the historicity of both.

Undesigned coincidence: Mark and John on the temple statement lock together to support historicity